Computer Simulations Outcomes of Left Atrial Arrhythmia Induction are Highly Sensitive to Scar and Fibrosis Determination

Personalized computational models used to guide ablation heavily depend on late gadolinium enhanced images for scar and gray area estimation. The estimation has a high degree of uncertainty, but it is unclear how sensitive the simulation outcome is to the specific scar. In this work, we study the sensitivity of the simulation outcome on the scar. Two personalized left atrial models were generated for a de-novo and a redo atrial. In control setting scar and gray area were obtained by thresholding LGE-MRI images at 70%, and 60% of the maximum myocardial intensity, respectively. This was compared against segmentations, generated by dilating, or eroding the control segmentation by one pixel, and increasing or decreasing the threshold by 5%. The outcomes were normal capture without further activity, extra beats with additional activity but not sustained, sustained arrhythmia with activity until the end of the simulation, and no capture. We found normally captured beats were not affected in redo cases but did change in de-novo ablation. However, extra beats were likely to change to arrhythmia when adding or subtracting scar. Sustained arrhythmia was sensitive to a reduction in scar size. This reiterates that attention is need when determining appropriate thresholds for scar and gray area.